Generalized Effects of Cold

Maintaining core temperature is a balance between heat lost and heat produced. When exposed to cold weather, the body's regulatory mechanisms induce measures to increase heat production. Shivering is one of the main ways that heat production is increased. Increased muscle activity generates heat as a byproduct. Other methods for increasing metabolism tend to take longer periods of time to develop and be of value.

Acclimation to the cold can help maintain function in the face of the cold exposure. However, the improvement is not as good as it is for heat. As exposure goes on, other mechanisms to increase body heat become useful, such as increased metabolism and skin circulation adaptations (33).

Performance decreases with body cooling, much as it does for hot temperatures. The very old and the very young are most sensitive to cold, just as they are to heat. Various medical conditions, hypothyroidism for example, make a person more sensitive to cold-related illness. Alcohol intake dilates skin blood vessels, making the person more sensitive and likely to develop significant cold-related problems (35).

The earliest manifestations of cold-related illness may be non-specific and include fatigue and clouded thinking. Increased muscle tone and shivering are an early part of the body's response to cold and attempt to maintain core temperature. The person may develop altered vision, social withdrawal, irritability, and uncoordinated movements. One paradoxical symptom is removing clothing despite the cold.

If the cold-related illness is left untreated, shivering may cease as the body fatigues and organs shut down. Cardiac arrest may develop leading to death. The timing and sequence of events depend on a number of factors but once started require immediate medical attention (33).

While cold-related problems are the result of cold exposure, overheating and heat-related problems can develop if the person over-exerts in the cold or has overdressed for the situation. This situation can lead to increased perspiration, dampness of clothing, and body cooling (34).